Silicon-controlled rectifier (SCR) based dimming can be used to achieve voltage regulation or dimming mainly by phase control. For example, the SCR can be turned on in each half cycle of a sine wave, to obtain a same conduction angle. The conduction angle can be changed by regulating operation time or phase of a trigger pulse. For example, an output voltage of a dimmer may be higher and a light can be brighter as the conduction angle is increased.